With mobile phones, sexy hardware is all very well–but the main purpose of sexy hardware is to run useful (or fun) software. And the vast majority of the software that today’s phones run is written not by phone operating system companies but by third-party developers.

So one of the very biggest questions about Microsoft’s upcoming Windows Phone 7 isn’t whether it looks slick and functional (it does) or if it’ll be a cakewalk for the company to reenter the mobile OS wars at this late date (it won’t). It’s whether enough software companies will build cool Windows Phone software quickly enough to make the platform feel like it’s part of the App Era.

As I’ve met with mobile software companies over the past few months, I’ve had a hard time getting a sense of Windows Phone 7’s prospects. Almost all the ones I’ve asked have said that they’re taking a wait-and-see attitude. But Microsoft has been holding an event at its Silicon Valley campus for some of the mobile developers who belong to its BizSpark program for startups. The companies at the meeting are convening in an auditorium to crank away at Windows phone 7 apps. Microsoft employees are providing both technical and business advice.

I visited with some of the developers yesterday–including name-brand companies and some I wasn’t familiar with–and came away feeling cautiously optimistic.

I saw rough drafts of Windows Phone 7 versions of several apps:

Ustream, the personal video broadcasting services (the WinPhone one will only offer viewing at first, not broadcasting);

PageOnce, which melds together information from your credit card accounts, bills, accounts, and other sources

Hint, from a stealthy startup called Cellixis which is building a “personal concierge” service to provide suggestions about restaurants and other local businesses–and which decided to scrap plans for an iPhone version and launch only on Windows Phone;

YomoMedia, which is bringing its Windows Mobile feed reader to Windows Phone 7.

The interesting thing about the applications I saw was that all the companies involved seemed to be working hard to build real Windows Phone 7 apps. Their WinPhone interfaces weren’t rehashes of versions for other platforms: They take advantage of distinctive WinPhone features like Live Tiles (which are hybrids of desktop icons and widgets) and Panorama view (which lets you drill into information by swiping through screens). If every Windows Phone 7 developer takes this approach, the ecosystem will feel more like the coherent universe of iPhone apps than like Android, where there’s hardly any consistency from one app to another.

I also chatted with some folks from social gaming company Digital Chocolate but didn’t see what they were working on. And social networking Loopt, digital comics company Graphic.ly, consumer electronics research service Retrevo, and other companies I didn’t speak with were at Microsoft’s event.

The fact that a bunch of developers are enthusiastic about Windows Phone 7 doesn’t guarantee anything, of course. The third-party apps the platform needs most are top-notch ones for services such as Facebook, Foursquare, Twitter, and Kindle–and there’s no official news about any of these yet. And while quality is more important than quantity, Windows Phone will also need a critical mass of apps in major categories. (This we already know: Every review of the first Windows Phone 7 handsets will note that iPhone and Android have vastly larger quantities of third-party programs than Windows Phone does.)

Ultimately, most developers are going to gravitate towards mobile OSes that offer the potential to reach lots of consumers and the possibility of making money. Even once Windows Phone 7 is out there, it’ll be a while before anyone can read its vital signs. (Hey, I was optimistic about the Palm Pre’s chances at first.) But Microsoft has a long history of being really good at making its platforms attractive propositions for third-party companies. It’s even funding the development of Windows Phone apps. If the WinPhone programs that are available on day one live up to the promise of the ones I saw, I think there’s a good chance that people will be pleasantly surprised by the third-party software situation.

Integrated Facebook support is important–I'd kill for it on the iPhone–but I think one of the many lessons of the Kin is that social stuff built into an OS can't replace standalone apps. For what it's worth, I asked a Windows Phone exec about standalone Facebook yesterday, and his response was that nothing had been announced–not "we won't need that, since it's built into the OS."

Does everything except personal video broadcasting. The question is why doesn't it broadcast?

Would this have something to do with the fact that Microsoft is running late, and has not finished writing many of the programming APIs in Windows Phone 7, including the VideoCamera API, and the Compass API, and the Sockets API?

Microsoft is repeating the Kin fiasco again. It is releasing an unfinished, half-baked product to market. With the fierce competition from Android and iPhone, a half-baked Windows Phone 7 will be DOA.

"The third-party apps the platform needs most are top-notch ones for services such as… Foursquare… and there’s no official news about any of these yet."

A Foursquare app was demonstrated live on stage by MS at their MIX presentation back in March – it was widely covered and widely praised at the time (some suggesting it was the nicest implementation they'd seen).http://www.artificialignorance.net/blog/windows-p…

True. I suspect that announcements of some of the bigger apps are being held back for the big push from MS once WP7 is ready to go. That's how I'd do it – use the availabilty of big apps at launch to counter the numbers games that Apple and Google (and some of their keener supporters) might play. Quality over quantity as it were.

i dont know how many apps will be there when win7 arrives in uk, but i am sure the push and muscle thrown by microsoft means, we will see something like windows7, a powerful product that will sweep the market. I also believe that there will be a large number of apps available going by the amount of publicity win7 is generating and will generate once the official date is announced. Facebook, twitter, foursquare, and a handful of apps, if are available in the begining, people will definately buy it coz win7 is stylish and these are the apps being used the most and once this happens i see 1000 of new apps arriving each day

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